warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:12:8
   |
LL |     if (fn_ptr as *mut ()).is_null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value
   = note: `#[warn(useless_ptr_null_checks)]` on by default

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:14:8
   |
LL |     if (fn_ptr as *const u8).is_null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:16:8
   |
LL |     if (fn_ptr as *const ()) == std::ptr::null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:18:8
   |
LL |     if (fn_ptr as *mut ()) == std::ptr::null_mut() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:20:8
   |
LL |     if (fn_ptr as *const ()) == (0 as *const ()) {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:22:8
   |
LL |     if <*const _>::is_null(fn_ptr as *const ()) {}
   |        ^^^^^^^^^^^^^^^^^^^^------^^^^^^^^^^^^^^
   |                            |
   |                            expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:24:8
   |
LL |     if (fn_ptr as *mut fn() as *const fn() as *const ()).is_null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:26:8
   |
LL |     if (fn_ptr as *mut fn() as *const fn()).cast_mut().is_null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:28:8
   |
LL |     if ((fn_ptr as *mut fn()).cast() as *const fn()).cast_mut().is_null() {}
   |        ^^------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |          |
   |          expression has type `fn() {main}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:30:8
   |
LL |     if (fn_ptr as fn() as *const ()).is_null() {}
   |        ^--------------^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `fn()`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: function pointers are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:32:8
   |
LL |     if (c_fn as *const fn()).is_null() {}
   |        ^----^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `extern "C" fn() {c_fn}`
   |
   = help: wrap the function pointer inside an `Option` and use `Option::is_none` to check for null pointer value

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:36:8
   |
LL |     if (&mut 8 as *mut i32).is_null() {}
   |        ^------^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&mut i32`

warning: returned pointer of `from_mut` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:38:8
   |
LL |     if ptr::from_mut(&mut 8).is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:40:8
   |
LL |     if (&8 as *const i32).is_null() {}
   |        ^--^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&i32`

warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:42:8
   |
LL |     if ptr::from_ref(&8).is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:44:8
   |
LL |     if ptr::from_ref(&8).cast_mut().is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: returned pointer of `from_ref` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:46:8
   |
LL |     if (ptr::from_ref(&8).cast_mut() as *mut i32).is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:48:8
   |
LL |     if (&8 as *const i32) == std::ptr::null() {}
   |        ^--^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&i32`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:51:8
   |
LL |     if (ref_num as *const i32) == std::ptr::null() {}
   |        ^-------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&i32`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:53:8
   |
LL |     if (b"\0" as *const u8).is_null() {}
   |        ^-----^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&[u8; 1]`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:55:8
   |
LL |     if ("aa" as *const str).is_null() {}
   |        ^----^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&str`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:57:8
   |
LL |     if (&[1, 2] as *const i32).is_null() {}
   |        ^-------^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&[i32; 2]`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:59:8
   |
LL |     if (&mut [1, 2] as *mut i32) == std::ptr::null_mut() {}
   |        ^-----------^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&mut [i32; 2]`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:61:8
   |
LL |     if (static_i32() as *const i32).is_null() {}
   |        ^------------^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&i32`

warning: references are not nullable, so checking them for null will always return false
  --> $DIR/ptr_null_checks.rs:63:8
   |
LL |     if (&*{ static_i32() } as *const i32).is_null() {}
   |        ^------------------^^^^^^^^^^^^^^^^^^^^^^^^^
   |         |
   |         expression has type `&i32`

warning: returned pointer of `as_ptr` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:67:8
   |
LL |     if ptr::NonNull::new(&mut 8).unwrap().as_ptr().is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: returned pointer of `as_ptr` call is never null, so checking it for null will always return false
  --> $DIR/ptr_null_checks.rs:69:8
   |
LL |     if ptr::NonNull::<u8>::dangling().as_ptr().is_null() {}
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: 27 warnings emitted